EEVblog Electronics Community Forum
EEVblog => EEVblog Specific => Topic started by: metalphreak on April 01, 2011, 02:25:06 pm
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Hey Dave,
Can confirm the same thing happens with a SGS THOMSON SOIC package 555!
Easter Eggs in everything. It's crazy.
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Hey Dave,
Can confirm the same thing happens with a SGS THOMSON SOIC package 555!
Easter Eggs in everything. It's crazy.
Yep confirmed it TODAY!
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I love Easter Eggs (on every date :p). In one of my projects containing an alphanumeretic lcd the "Easter Egg" was instructions for obtaining the source code.
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Interesting.
Looking at the internal schematic of the 555 doesn't explain it. If it's deliberate, then there's more to the schematic than the datasheet gives, if it's a coincidence there's some parasitic element inside the IC which is to blame.
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It works with National LM7555 (CMOS version), but only at a supply voltage of 7.555 volts.
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It works with National LM7555 (CMOS version), but only at a supply voltage of 7.555 volts.
Lol, you can't be serious. Perhaps Dave should test this?
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I think I should show this video to my digital circuits class today ;)
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Yep,
But it doesn't seem very stable on my end.... Will have to test again tomorrow to see if it works again ;)
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Lol, surely you can't be serious.
I am serious. And don't call me Shirley.
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Wow, this is pretty cool! I'll see if I can give it a try.
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Interesting.
Looking at the internal schematic of the 555 doesn't explain it. If it's deliberate, then there's more to the schematic than the datasheet gives, if it's a coincidence there's some parasitic element inside the IC which is to blame.
Hans was a clever designer, I'm sure it's very subtle...
Dave.
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It works with National LM7555 (CMOS version), but only at a supply voltage of 7.555 volts.
Awesome, will have to try it.
Hans was bought back to design the 7555, so makes sense he put something in that too.
Dave.
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I wonder what would happen if you made a 555 out of discrete components.
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Am I the only one that thinks April Fools??
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Am I the only one that thinks April Fools??
Of course, lol, I can't believe we fell for it.
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A question would be "how did he do it ?".
I guess the scope leads don't connect to the breadboard at all but to some signal generator with a modulation input ?
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What didn't make sense to me was the frequency seemed to be changing slightly, yet he detected the modulation using a simple low pass filter which shouldn't work, so it should've been obvious something was a miss.
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I guess the scope leads don't connect to the breadboard at all but to some signal generator with a modulation input ?
I can assure you, the scope leads were connected directly to the 555 as explained.
Dave.
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The circuit doesn't match the schematic.
The pot is really 200R rather than 500R and then there's all those resistors connected in parallel.
The pot should also never be allowed to go too low otherwise it'll burn out the discharge transistor in pin 7 so there should be a fixed resistor in series with it.
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I can assure you, the scope leads were connected directly to the 555 as explained.
Dave.
Is there a prize for figuring out how you did it? ;)
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It matches.
As mentioned, the values are approximate.
Only found a 200R pot in my kit, so used a series resistor as well.
The 1k5 is made with 3 resistors to tweak the value so I could get the range needed.
No trickery in the resistors at all.
Dave.
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I hope there's a reveal coming up then.
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and that's a normal 555 timer not some uC in DIP8 ? ;) I don't suppose Dave did something with Agilent scope heh.
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Not just an engineer, but a magician also apparently.
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and that's a normal 555 timer not some uC in DIP8 ? ;) I don't suppose Dave did something with Agilent scope heh.
Yep, brand new bog standard National 555 timer.
Try harder!
Bueller?, Bueller?
Dave.
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Are you putting the signal in through the power supply?
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I posted this in another forum...the response is skeptical.
http://www.physicsforums.com/showthread.php?p=3226304#post3226304 (http://www.physicsforums.com/showthread.php?p=3226304#post3226304)
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Doesn't seem they are being skeptical as much as they are just being asshats.
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Are you putting the signal in through the power supply?
Dave used batteries also.
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Take a look Here
555 Easter Egg and Ground Loops (https://www.youtube.com/watch?v=BJNhVb_JO0U#ws)
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Could you explain some things? Are you saying there is not only 55.5kHz but also it's harmonics at 111kHz ? sorry but I couldn't understand few words on your video probably due to accent ;) Or maybe you wanted to show Us that there is something injected to the signal through a ground loop of the probes ?
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It's not my video :) Just found it on YouTube.
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oh, OK :) Any ideas then ?
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As I understand it he says that it also modulates at 111hz at 111khz carrier ie twice Daves frequency. 55khz could be the fundamental frequency or another harmonic, still not convinced that there isn't some sneaky business going on but it's beyond me, just have to wait for Dave to come clean or someone to crack it........watch this space ;)
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Quote from the video author found on youbtube :
If he has done it like me, than there is a hidden wire to the control voltage pin, from an external sine generator, adjusting the level with another? pot outside the camera view. Of course, if you add a capacitor from this input to ground, the modulating signal will be shorted :-)
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Perhaps Daves April Fool will get to be as famous as this
http://news.bbc.co.uk/onthisday/hi/dates/stories/april/1/newsid_2819000/2819261.stm (http://news.bbc.co.uk/onthisday/hi/dates/stories/april/1/newsid_2819000/2819261.stm)
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As I understand it he says that it also modulates at 111hz at 111khz carrier ie twice Daves frequency. 55khz could be the fundamental frequency or another harmonic, still not convinced that there isn't some sneaky business going on but it's beyond me, just have to wait for Dave to come clean or someone to crack it........watch this space ;)
That makes sense, so it/s not just the frequency which changes, varying the voltage on pin 5 also varies the duty cycle which can be detected with a simple RC filter.
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Doesn't seem they are being skeptical as much as they are just being asshats.
I found this slightly amusing:
One person: I want to know what brand solder flux that guy is using and how much he's inhaling.
Another person: Holy jeez, I know! He is rather obnoxious.
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I do not detect any extra wires going to the breadboard, but I notice that Dave is working on top of a thin mat. So I am going to suggest a loop antenna underneath transmitting the 55.5Hz signal. With the cap missing, the breadboard spring would need to pick up well enough to put a few tens of mV swing onto the control pin (which is connected to the 5k-5k divider internally).
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Dave must be reading too much of 'Harmonic 695'! Maybe time to get out our tin foil hats :)
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Doesn't seem they are being skeptical as much as they are just being asshats.
I found this slightly amusing:
One person: I want to know what brand solder flux that guy is using and how much he's inhaling.
Another person: Holy jeez, I know! He is rather obnoxious.
I get comments like that all the time!
They wouldn't now what enthusiasm is if it bit them on the arse.
Dave.
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Can we get a Detail Sketch (all the values and where you took your measurement).
I am new to electronics and just got myself a oscilloscope and I can't get the same wave form as you did. Sorry n00by speaking.
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Very interesting 1/2 second or so at about 2:15 are those wires to the bottom of the bread board? aerial?
https://www.youtube.com/watch?v=XZ4r8Rc5aus&feature=player_embedded#t=135s (https://www.youtube.com/watch?v=XZ4r8Rc5aus&feature=player_embedded#t=135s)
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Doesn't seem they are being skeptical as much as they are just being asshats.
I found this slightly amusing:
One person: I want to know what brand solder flux that guy is using and how much he's inhaling.
Another person: Holy jeez, I know! He is rather obnoxious.
I get comments like that all the time!
They wouldn't now what enthusiasm is if it bit them on the arse.
Dave.
Ha! You said arse...
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Very interesting 1/2 second or so at about 2:15 are those wires to the bottom of the bread board? aerial?
haha, busted i think
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You meant that ?
(http://img839.imageshack.us/img839/3677/dave555.jpg) (http://img839.imageshack.us/i/dave555.jpg/)
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Yep! Looks suspiciously like an aerial coil or a pair of wires to me, could be just a wire clipping but the breadboard seems to be stood on some sort of mat. Makes me suspect some sort of magnetic loop or rfid type of thing (running out of ideas so any straw looks good ;D)
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Just listened to the latest AmpHour. Definitely sounds like you nailed it FreeThinker!
Good thing Dave doesn't work for the CIA/NSA/FBI. ;D
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Yahhh! Do I get a prize? Lol. .......perhaps a Tshirt 'I Sussed Dave 04/2011' (With my luck it would be one of those bloody lcd's he's trying to shift) Looking forward to to the reveal to find out exactly how it was done ;D ;D ;D
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Check out my video response www.n1ir.com (http://www.n1ir.com) . Breadboarded multiple times multiple chips and still could not get it to oscillate? Watch video 7 and see me build it up. Might be a ground loop or picking up the mains (50 hz) all I can think of?
N1IR, Mr J.
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Reveal has been posted. Nice one!
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I get comments like that all the time!
They wouldn't now what enthusiasm is if it bit them on the arse.
Going by the comments, they also lack a sense of humour.